It means "Are you there?"
Esta usted/estas alli? (accents on 'a' in estas/esta; 'i' in 'alli')
estas ayi? (spelt 'estas alli?')
"Con quien estas" translates to "who are you with" in English.
"Que estas haciendo" translates to "What are you doing" in English.
No estas casada translates to mean you are not married in English.
you are
"y como estas" in English is: "And how are you?"
"Estas en la escuela" in English means "You are at school."
Ésta allí---This one (noun in fem. gender) over there
"que estas bien" phrase could be translated as English "be well" or "take care" when leaving
Are you there, friend?
"Are you possessed?"